I. Field of the Present Invention
The present invention relates generally to motor vehicle constructions, and more particularly, to a vehicle construction in which modular sections are fabricated and assembled with operating components before the individual modules are mounted together to form a complete vehicle.
II. Description of the Prior Art
The construction and assembly of a motor vehicle is a complex project due to the large number of components which must be manufactured, assembled and installed to produce the finished motor vehicle. Although the use of an assembly line to produce vehicles of a particular model has organized and increased the efficiency of motor vehicle production, there are a large number of operations which must be performed on the assembly line. Therefore, a problem occurring at any point along a continuous assembly line can substantially affect the output production of the entire assembly line.
Moreover, in view of the fact that each vehicle may be differently constructed from vehicles of the same model due to the demand for different functional components, optional equipment, trim style and color, the actual production operation performed at each station of the assembly line may differ for each vehicle-in-production. Consequently, mass production of a particular vehicle model can be further complicated. Nevertheless, it has been typical to utilize a continuous, comprehensive production line for each model of motor vehicle produced by a manufacturer. Although the actual construction of the various components which are mounted to the vehicle-in-production as it proceeds along the production line may be performed apart from the assembly line facility and process, the timely supply of such components at the necessary station of the production line has a substantial effect on the entire production of the vehicles on the assembly line.
Although timely mounting of vehicle components at each station along a production line has been aided by the introduction of mechanized and robotic devices which can be programmed to repeatedly perform various manufacturing processes along the assembly line, even when the processes are subject to change for each vehicle being constructed, the production rate of the entire assembly line is dependent upon proper operation of each individual station along the assembly line. Moreover, as more and more parts are added to the vehicle-in-production, the installation and assembly of other components becomes more complicated. . In particular, previously attached assemblies can interfere with free access to the areas at which additional parts are to be mounted or installed, and can substantially increase the difficulty of performing the necessary operations.
A particularly troublesome feature of previously known assembly lines is that the application of corrosion resistant coatings such as the application of paint is a particularly time consuming operation. Not only must the paint be applied in an even and comprehensive manner, but the paint or other coating must be dried or cured before additional assembly can continue. Moreover, repeated painting operations create substantial control problems with overspray and the release of chemical solvents.
It has been known to apply the final paint coating only after all the major parts of the vehicle have been assembled. However, such a process requires that portions of the vehicle be masked to prevent undesirable overspray, it prevents the application of paint on unexposed areas of the vehicle, and requires a substantial amount of dedicated floor space. Alternatively, it has also been known to construct a body assembly from a plurality of stamped panels which have been welded together, separately and apart from construction of the vehicle chassis, so that the body assembly can be fully coated. In addition, such a body assembly can be immersed in an electroplating bath to provide improved corrosion resistance. However, if other exterior components such as doors are unable to be coated at the same time as the assembled body panels, it is necessary to assure that the finish used to coat the doors does not differ substantially from the finish coating applied to the other panels in order to provide the finished vehicle with a proper consistent appearance. Moreover, a large amount of dedicated floor space is still necessary for a complete body.
In addition, the interest in producing sturdy but lightweight vehicles to improve the handling characteristics and fuel economy of motor vehicles can substantially affect production line assembly of motor vehicles. For example, although it has been known to utilize body panel structures as support structures to reinforce the chassis frame of a motor vehicle, the assembly of the body structure together with the chassis frame can substantially interfere with the installation of the drive train, running gear and other components such as passenger compartment instrumentation which are necessary to produce a complete vehicle. In particular, access to the locations at which such components are installed can be severely restricted by the body panels. Moreover, the previously mentioned problems of paint matching and painting time are equally troublesome in production line assembly of motor vehicles of this type.